LP12 suspension susceptible to acoustic feedback


My turntable setup: LP12 (early 80s model, unmodified except for Nirvana springs), Syrinx PU2G, Shure M95-HE.

When I place the arm/cartridge on a (stationary) LP, the entire arm board and arm rest resonates to light finger taps, and the sound emerges as rather loud thuds through the speakers, at normal listening levels.

When the arm/cartridge is lifted off the LP, the feedback is minimised.

My LP12 rests on three light wooden blocks (the sort kids play with), a marble slab, a wooden slab and four sheets of thick plate glass, in that order.

I'm thinking of getting an IKEA Lack table for the LP12.

Any solutions to eliminate, or minimise the feedback?

Thanks.

Becks
tubemoose
Sounds like you have too much under the TT. I use Aurios under my LP12 and get great results. I have on a cabinet that is braced to the wall behind it to control any lateral movement. And with the Aurios under a single shelf that the TT sets on I have no issues except extreme foot fall.
Have you considered just getting a wall shelf? I don't think the marble and glass are a good idea and I would try it without them. I suspect that they are reflecting back the energy when you tap the table. You would be better off with a support that dissipates energy or a set up like Theo's. I have a similar Linn which I use occasionally but haven't noticed this when it is on my TNT stand or Star Sound rack. If there is a good Linn set up tech close I would have the suspension checked.
Thanks Theo and Stanwal. I have not considered wall mounting.

By the way, I forgot to mention that the floor of my apartment is solid concrete and tile, so I have no issue with footfalls, unless there's an elephant in the room :)

If there is too much mass underneath (and I suspect Theo and Stanwal are right about this) the lightweight IKEA Lack table may be the answer.

Thanks.

Becks
If you have a concrete floor than you don't need a wall shelf. Just the a good solid stand will do. But I would tie the elephant up out back when playing records as mine used to want to dance and he might bump the TT stand.
It was sad when he died. Plumber told me I should have buried him instead. Even if it worked for the goldfish, I know now that buriel was the way to go.
Since the beginning of time, or at least as long as the Sondek has been
around Ivor Tiefenbrun and Linn dealers have recommended only a light and
rigid shelf below the LP12 for best sonic results.

I understand testing a theory because so little is absolute yet, when the
designer and builder calls for a specific foundation, maybe there is something
to it.

There is not a TT on earth made to withstand "When I place the
arm/cartridge on a (stationary) LP, the entire arm board and arm rest
resonates to light finger taps, and the sound emerges as rather loud thuds
through the speakers, at normal listening levels.' this is not a valid test of TT
resonance mismanagement... sorry.

Personally I have found most suspension TT's to give excellent results with
the same (a light rigid shelf).

The Ikea Lack is such a table.

Happy Listening!
R f Sayles is absolutely correct!